filereplacement.java

这是linux下ssl vpn的实现程序

package com.sslexplorer.vpn.util;

import java.util.Hashtable;
import java.io.File;
import java.io.IOException;
import java.util.Enumeration;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.io.FileOutputStream;
import java.util.Random;
import java.io.ByteArrayOutputStream;


/**
 * This utility will take an input file and replace any number of
 * tokens before outputing it to an output file, which may or may
 * not be temporary.
 *
 * @author Lee David Painter
 * @version $Revision: 1.8 $
 */
public class FileReplacement {

    Hashtable tokens = new Hashtable();
    File templateFile;
    File outputFile;
    File cwd;
    String parameter;
    String encoding = "UTF8";

    public FileReplacement(File cwd) {
        this.cwd = cwd;
    }

    public String getId() {
        return parameter;
    }

    void processReplacementXML(XMLElement el, ApplicationLauncher launcher) throws IOException {
        if(!el.getName().equalsIgnoreCase("replacements")) {
            throw new IOException("Error! Element is not <replacements>");
        }

        if(el.getAttribute("templateFile")==null) {
            throw new IOException("Error! <replacements> element requires 'templateFile' attribute");
        }

        templateFile = new File(cwd, el.getAttribute("templateFile").toString());

        if(launcher.events!=null)
            launcher.events.debug("Template file will be " + templateFile.getAbsolutePath());

        if(el.getAttribute("outputFile")!=null) {
            outputFile = new File(cwd, el.getAttribute("outputFile").toString());
        } else {
            outputFile = getTempFile(cwd);
        }

        if(launcher.events!=null)
            launcher.events.debug("Output file will be " + outputFile.getAbsolutePath());

        if(el.getAttribute("parameter")==null) {
            throw new IOException("Error! <replacements> element requires 'parameter' attribute");
        }

        parameter = el.getAttribute("parameter").toString();
        launcher.addParameter(parameter, outputFile.getAbsolutePath());

        if(el.getAttribute("encoding")!=null)
            encoding = el.getAttribute("encoding").toString();

        if(launcher.events!=null)
            launcher.events.debug("Output file will be encoded in " + encoding);

        for(Enumeration e = el.getChildren().elements(); e.hasMoreElements();) {
            XMLElement child = (XMLElement)e.nextElement();

            if(!child.getName().equalsIgnoreCase("replace")) {
                throw new IOException("Error! <" + child.getName() + "> is not a supported element of <replacements>");
            }

            if(child.getAttribute("token")==null || child.getAttribute("value")==null) {
                throw new IOException("Error! <replace> element requires 'token' and 'value' attributes");
            }

            tokens.put(child.getAttribute("token").toString(), child.getAttribute("value").toString());
        }

    }

    void createReplacementsFile(ApplicationLauncher launcher) throws IOException {


        FileInputStream in = new FileInputStream(templateFile);
        ByteArrayOutputStream tmp = new ByteArrayOutputStream();

        byte[] buf = new byte[4096];
        int read;

        while((read = in.read(buf))>-1) {
            tmp.write(buf, 0, read);
        }

        // First replace all standard parameters etc
        String outputContent = launcher.replaceTokens(new String(tmp.toByteArray(), encoding));

        for(Enumeration e = tokens.keys(); e.hasMoreElements();) {

            String token = (String) e.nextElement();
            String value = (String) tokens.get(token);

            if(launcher.events!=null)
                launcher.events.debug("Processing replacement token " + token + "=" + value);

            // Perform replacement in String
            outputContent = ApplicationLauncher.replaceAllTokens(outputContent, token, value);

        }

        FileOutputStream out = new FileOutputStream(outputFile);
        try {
            out.write(outputContent.getBytes(encoding));
        }
        finally {
            out.close();
        }

        ClientCacheRemover.getInstance().trackFileForRemoval(outputFile);

    }

    static File getTempFile ( File near ) throws IOException {
       String path = null;
       if ( near != null )
          if ( near.isFile() ) path = near.getParent();
          else if ( near.isDirectory() ) path = near.getPath();

       Random wheel = new Random(); // seeded from the clock
       File tempFile = null;
       do
          {
          // generate random a number 10,000,000 .. 99,999,999
          int unique = ( wheel.nextInt() & Integer. MAX_VALUE ) %90000000 + 10000000;
          tempFile = new File( path, Integer.toString ( unique) + ".tmp" );
          } while ( tempFile.exists() );
       // We "finally" found a name not already used. Nearly always the first time.
       // Quickly stake our claim to it by opening/closing it to create it.
       // In theory somebody could have grabbed it in that tiny window since
       // we checked if it exists, but that is highly unlikely.
       new FileOutputStream( tempFile ).close();

       // debugging peek at the name generated.
       if ( false )
          {
          System.out.println( tempFile.getCanonicalPath());
          }
       return tempFile;
} // end getTempFile
}